Column space of a matrix

Hi there,

I would like to find the column space of a matrix, but don't want the basis to be orthonormalised.

I tried the colspace function, but it seems to orthonormalise the basis.

For instance,

A = [1 0.2 3; -1 0.3 1; 2 -4 7];

colspace(sym(A))

Gives the answer:

[ 1, 0, 0]

[ 0, 1, 0]

[ 0, 0, 1]

However, in this particular example I would expect the first three columns of the matrix A as the answer if no orthonormalisation is done.

Any ideas how to achieve this?

Thanks and regards....

Answer 1

[Matt J]

You can use this FEX submission,

https://www.mathworks.com/matlabcentral/fileexchange/77437-extract-linearly-independent-subset-of-matrix-columns

Example:

A =

    1.0000    0.2000    3.0000    1.0000    0.2000    3.0000
   -1.0000    0.3000    1.0000   -1.0000    0.3000    1.0000
    2.0000   -4.0000    7.0000    2.0000   -4.0000    7.0000

>> licols(A)

ans =

    1.0000    0.2000    3.0000
   -1.0000    0.3000    1.0000
    2.0000   -4.0000    7.0000

[othusitse molokele]

It gives wrong answer

[Rik]

@othusitse molokele Can you give an example?